Add test for slice as prefix/suffix pattern

Signed-off-by: Ian Jackson <[email protected]>

Author: ijackson

library/core/src/slice/mod.rs

@@ -1783,6 +1783,10 @@ impl<T> [T] {
     /// assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
     /// assert_eq!(v.strip_prefix(&[50]), None);
     /// assert_eq!(v.strip_prefix(&[10, 50]), None);
+    ///
+    /// let prefix : &str = "he";
+    /// assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
+    ///            Some(b"llo".as_ref()));
     /// ```
     #[must_use = "returns the subslice without modifying the original"]
     #[stable(feature = "slice_strip", since = "1.50.0")]